This application is directed to dimercaptothiadiazole-derived reaction products which have multifunctional antioxidant/antiwear properties when incorporated into oleagenous compositions.
The use of dimercaptothiadiazole derivative, such as 2,5-dimercapto-1,3,4-thiadiazole, has been well known for their antioxidancy, anticorrosion, and metal passivation properties in a variety of lubricant applications, as disclosed in U.S. Pat. No. 4,661,273, U.S. Pat. No. 4,678,592 and U.S. Pat. No. 4,584,114.
The use of alkenyl succinic acid-esters has been reported as rust inhibitors and dispersants for many lubricating oils and greases.
The use of amine salts, such as amine phosphate salts, has found widespread commercial use for several decades as antiwear/EP additives.
Replacement of zinc phosphorodithioates by zinc/phosphorus-free antiwear additives in engine oils, circulating oils, gear oils and various other lubricating systems is currently considered desirable. The products of the present invention provide outstanding FZG gear performance, low four-ball wear and good antioxidant activity, and most important, are zinc/phosphorus free. Therefore, these products are good canditates for the replacement of zinc phosphorodithioates in many lubricant formulations.